This invention relates to a passage width adjustment of a sliver trumpet which is associated with a measuring device for determining the thickness and irregularities of a running fiber sliver, particularly in spinning preparation machines such as carding machines. The measuring member is installed in the sliver trumpet which, in turn, serves for compressing (densifying) the throughgoing sliver.
For different sliver numbers the sliver trumpet must have different constrictions (outlet openings) in the zone of the sliver sensor. In a device disclosed in published European application 252,952, at the sliver trumpet a measuring member is arranged which senses the thickness and irregularities of the sliver in a measuring channel. For making adjustments for different sliver numbers, the measuring channel is provided in a replaceable measuring component mounted in the sliver trumpet. Thus, in this arrangement, the measuring component is replaced ever time the sliver number is changed. Such a replacement of the sensor location proper is circumstantial, expensive and repeatedly requires compensation measures.